Device for releasably gripping an elongate flexible member

ABSTRACT

A device for releasably gripping an elongate flexible member, such as a webbing strap extending therethrough, and wherein gripping surfaces of the device are resiliently urged by a loading spring into pressure engagement with the strap, manually operable camming means being provided for releasably varying the pressure engagement resulting from the loading spring, so as to permit relative restrained movements between the gripping surfaces of the device and the webbing strap under load stressing forces applied between the webbing strap and the device.

Uite States atet Eisner Feb. 13, 1973 [54] DEVICE FOR RELEASABLYGRIPPING 1,482,268 1 1924 Schopper ..l88/65.l

AN ELONGATE FLEXIBLE MEER 75 Inventor: Edwin c. Eisner, Kanosh, Utah jgi ggs i g m [73] Assignees: Max Fink; Floyd C. Hahn; Hugh W.Attorney-Whann & Mc Manigal Littlebury, Sr., Los Angeles County, Calif.part interest to each ABSTRACT [22] Filed;. Nov. 27, 1970 A device forreleasably gripping an elongate flexible member, such as a webbing strapextending [21] 93074 therethrough, and wherein gripping surfaces of theI device are resiliently urged by a loading spring into 52 us. Cl..l88/65.1, 188/166 pressure engagement with the S p manually p [5l]Int. Cl. ..B65h 59/61 ble camming means being Provided for releasably[58] Field of Search ..l88/65.l, 65.4, 65.5, 166; varying the Pressreengagement resulting from the 24/248 11,2633 loading spring, so as topermit relative restrained movements between the gripping surfaces ofthe References Cited device and the webbing strap under load stressingUNITED STATES PATENTS 6/1884 Greene 188/655 forces applied between thewebbing strap and the device.

11 Claims, 7 Drawing Figures DEVICE FOR RELEASABLY GRIPPING AN ELONGATEFLEXIBLE MEMBER BACKGROUND OF THE INVENTION The present inventionrelates generally to strap and cable clamping devices.

Heretofore, it has been generally known to provide a variety of devicesand schemes for manually releasably controlling the paying out offlexible members such as ropes, straps, cables, and the like, whilebeing subjected to load tensioning forces. For example, in mountainclimbing, it is common practice in repelling for the climber to pass arope around his body, and through rings in such a manner as to placeportions of the rope in a bite which can controllabely be released topermit lowering of the body along the rope. In some cases, it has beenthe custom to pass the rope through staggered slots in such a way as toprovide releasable control.

Presently, there is need for a cable or strap gripping device which canbe effectively and simply used in a safe manner for the controlledlowering of suspended loads attached to the device, or to the associatedflexible member. Such a device finds a particular beneficial use, forexample, as means for debarking and lowering loads from a hoveringhelicopter, in rescue work,-and many other situations.

Recently, a cable clamping device has become generally known in ()5.letters Pat. No. 3,528,139, which issued on Sept. 15, 1970. Briefly, thedevice of this patent comprises a clamping unit designed with a view toproducing a self-clamping action due to the traction exerted by thecable supporting the load, the

as a webbing strap, and is more particularly concerned with such adevice wherein the clamping forces can be releasably controlled topermit restrained movements between the device and flexible member undera condition of applied load stressing forces.

One object of the invention is to provide a device of the hereindescribed character for clamping or gripping a flexible member, which isso arranged that the device may be anchored and utilized to feedinglycontrol movement of a load stressed strap therethrough, or converselypermit the strap to be anchored and manual control of the movement ofthe device therealong together with an attached load.

A further object is to provide a clamping device of the above typehaving unique means for applying an adjustable pre-determined grippingforce to an associated flexible member, together with manuallyactuatable means for variably relieving the gripping force in a mannerto control relative movements under load stressing forces appliedbetween the flexible member and the device.

gripping force increasing with the cable tension. Spring meansconstantly urge, by means of linkages, the jaws in clamping direction,and manually operable levers are provided for releasing the jaws.

A study of this patent, however, indicates that devices such as thepatented device are not adaptable for use in the particular fields, andunder the conditions, in which the device of the present invention isparticularly beneficial. The patented device lacks the required nicetyof regulation which permits the clamping holding force to be reduced insuch a way as to permit arestrained movement of the device with respectto the gripped flexible member. Moreover, while the patented deviceshows the utilization of springs for creating a pre-clamping force,these springs do not operate in the same manner as in 'applicantsinvention, nor is the urging force of these springs varied to obtain theadvantageous results which are obtained in the device of the presentinvention. In the device of the present invention, the inherentdisadvantages of the device disclosed in the above patent have beeneliminated by providing an elongate pivoted structure wherein aleaf-spring is pre-stressed to urge a roller gripping member against theflexible member, in this case a webbing strap, a camming lever beingprovided which permits flexing of the spring so as to controllablyreduce the gripping pressure against the webbing strap and permitrestrained controlled movements between the device and the strap underapplied load stressing forces.

SUMMARY OF THE INVENTION The present invention relates generally to adevice for clamping engagement with a flexible member, such Anotherobject is to provide an improved device for releasably gripping anelongate flexible member, and which utilizes a pressure or grippingmember that is spring loaded against the flexible member, andincludoperable to adjustably and controllably relieve a predeterminedspring pressure applied to a gripping member, the lever being foldableto an out-of-the-way position when not in use Additional objects andfeatures relate to the provision of the following:

a. The utilization of a serrated rotatable gripping sleeve member havinga toothed outer surface, the sleeve member being mounted on areplaceable oil-filled bronze bushing.

. A cooperable gripping surface, opposite the gripping sleeve member,which is impregnated with a wear-resisting material such astungstencarbide.

A unique mounting for the gripping sleeve member and associated loadingspring, wherein floating movement enables proper and effective seatingof the gripping sleeve member.

. The utilization of a side opening channel permitting lateralpositioning of the associated flexible webbing strap therein, andwherein the associated structure including the loading spring isprovided with retaining means for holding the webbing in the channel.

The provision of a safety locking pin for the spring latching andtensioning means.

Further objects and advantages of the invention will be brought out inthe following part of the specification, wherein detailed description isfor the purpose of fully disclosing a preferred embodiment of theinvention without placing limitations thereon.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of adevice embodying the features of the herein describe invention, theparts being shown in opened position for receiving a flexible memberwith which it is to be associated;

FIG. 2 is a similar view showing the parts in closed clamped positionwith the inserted flexible member;

FIG. 3 is an elevational front view of the device, when applied as shownin FIG. 2;

FIG. 4 is a transverse section, taken substantially on line 4-4 of FIG.3, and showing details of the mounting of the rotary gripping means;

FIG. 5 is a transverse section, taken substantially on line 55 of FIG.3, showing certain details of the mounting for the release controlmeans;

FIG. 6 is a transverse sectional view, taken substantially on line 6-6of FIG. 3, showing details of the spring latching and tensioning means;and

FIG. 7 is a longitudinal section taken substantially on line 7-.-7 ofFIG. 3, and illustrating the cooperative relationship of the componentsof the clamping device with the elongate flexible member.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more specifically tothe drawings, for purposes of illustration, the present invention isshown in FIG. 1 as comprising generally a body structure B which carriesa pivotally mounted gripping means G and associated spring means S whichare adapted to be latched into an operating position by means of alatching and tensioning means L, wherein the gripping means will beresiliently urged against an associated webbing strap W. A releasecontrol mechanism R is manually operable to release the loading pressureof the spring S and permit controlled relative restrained movementsbetween the gripping means and the webbing strap under load stressingforces applied between the webbing strap and the device.

- More specifically, the body structure comprises an elongatesubstantially rectangular back plate 10 of high strength steel or othersuitable material. At the opposite ends, the back plate 10 is providedwith rigid connector loops 11, 11.

On the opposite side of the back plate 10 from the connector loops 1 1,transversely extending finger plate members 12a, 12b and 120 aresupported in spaced relation to the back plate by spacers 13a, 13b and13c, respectively, these finger plates being secured to edge projectionsof the back plate as by securing bolts 14 in each case. It will be notedthat the finger plate 12a is at one end of the back plate, and that thefingerplate 120 is at the opposite end, while the finger plate 12b isintermediate the ends of the back plate. As thus located, the fingerplates cooperate with the adjacent surface of the back plate to providein effect channel means having an opening at the side for laterallyreceiving edgewise thereinto the webbing strap W. Insertion of the strapmay be facilitated by angularly deflecting the outer ends of the fingerplates, and providing deflected cooperating spaced finger projections,as indicated at 15a and 15b, on the back plate in underlying relation tothe adjacent finger plate deflected portion.

Normally, the inserted webbing strap W is freely movable lengthwise inthe body structure. It is a feature, however, of the present inventionto provide unique means for restraining free movement of the webbingstrap by providing spring loaded gripping means as will now bedescribed. For this purpose, there is provided a bracket structure, asgenerally indicated at 16, which is formed with spaced leg portions 17and 18 (FIG. 3) adapted to straddle a rib 19 formed on the finger plate12a and to which it is pivotally floatingly supported for swingingmovement by means of pivot bolt 20. As shown in FIG. 7, the pivot bolt20 is mounted in a loose fit relation in an opening 21 of the rib 19 sothat this bracket may accommodate the gripping means with respect to theassociated webbing strap. Rotative movement of the bracket structure 16is limited in a clockwise direction, as seen in FIG. 7, by an angularabutment surface 22 on the underside of each of the leg portions 17 and18.

On the opposite side of the pivot bolt 20, the bracket structure 16 isprovided with extended side flanges 23 and 24 which serve as mountingmembers for the strap gripping elements. As will be seen, a cylindricaloil filled bronze bushing 25 is fixedly but removably mounted betweenthe flanges by means of supporting screws 26 and 27 which have theirinnermost ends threadedly engaged in the ends of the bushing. A washer28 is preferably placed under the head of each mounting screw, and awasher 29 interposed between each end of the bushing 25 and the adjacentside flange. The bushing 25 rotatably supports a cylindrical sleeve 30,the outer surface of this sleeve being serrated to provide a toothedsurface 31 for non-slipping engagement with the associated webbing strapW during operation of the device. As will be seen in FIG. 4, the

side flanges 23 and 24 in the strap engaging position of the grippingmeans, extend past the back plate and serve to retain the webbing strapW within the strap receiving channel.

The bracket 16 also carries a loading spring which comprises an elongategenerally rectangular leaf spring element 32 which is formed at one endwith spaced end projections 33 and 34 providing leg attachments securedto the leg portions 17 and 18, respectively, of the bracket structure 16by means of mounting bolts 35, 35. As thus mounted, the leaf spring 32extends axially along the back plate 10, and the outermost end of thisspring will be positioned adjacent the opposite end of the back platewhere it is operatively associated with the latching and tensioningmeans L which will be subsequently described in detail.

As best shown in FIG. 7, means are provided for adjustably varying thenormal position of the leaf spring 32 with respect to the bracketstructure 16 on which it is supported. For such purpose, the legportions 17 and 18 are each provided with an adjustable abutment screw36 which underlies and is engageable with the adjacent end of the leafspring element inwardly of the mounting bolts 35, 35. It will thus beevident that with the mounting bolts 35, 35 in loosened condition, theabutment screws 36, 36 may be raised and lowered so that when themounting bolts 35, 35 are again tightened, the position of theseabutment screws will determine the angular relationship of the leafspring and the supporting bracket 16. This will determine the amount ofloading spring force which will be applied to the gripping means G.

The latching and tensioning means L are supported upon the finger plate12c as shown in FIG. 6. The finger plate 12c is fabricated with a lug 37to which one end of a link member 38 is pivotally connected by a pivotpin 39. A latching lever 40 is constructed with a hand gripping portion,and at one end is formed with a head portion 41 having spaced endflanges 42 and 43 (FIG. 6) adapted to straddle the other end of link 38to which it is connected by a pivot pin 44. The latching lever and link38 as thus connected form an articulated linkage for clampinglyretaining and anchoring the outer end of the leaf spring element 32 in atensioned anchored position with respect to the finger plate 12c. Atthis end of the spring, an end slot 45 permits the spring end to movefrom a position as shown in FIG. 1 to a latched position as shown inFIG. 7 wherein the lug 37 and associated link 38 will be straddled andpermit actuation of the latching lever 40 into a latched position asshown in FIG. 7. The end flanges 42 and 43 have outer edge cammingsurfaces 46, 46 respectively, which will operate to force the springinto a deflected tensioned position as the latching lever reaches afully latched position, at which point straight-edge portions 47, 47,respectively, on the flanges 42 and 43 will produce over center dwellpoints which will operate to retain the latching lever in latchedposition. As a safety feature, a latch pin 48, which is connected withthe latching lever 40 by means of a flexible cable 49, may be insertedin aligned openings 50, 50, provided in the end flanges 42 and 43 toretain the latching lever against movement to unlatched position. Theoperative position of the latch pin 48 to hold the latching lever isclearly shown in FIG. 3.

Retention of the webbing strap within the receiving channel of thedevice by the side flanges 23 and 24 as previously explained, isaugmented at the latching 'end of the spring by means of a projectinglug 51 which is riveted or otherwise secured by conventional means atthe outer end of the leaf spring element 32. This lug is adapted to becarried endwise into a slot or opening 52 at the free end of the fingerplate 120, as shown in FIG.

6. In the latched position, the lug 51 projects past the back plate 10,in which position it opposes-outward movement of the webbing strap fromthe body channel. The mechanism as thus far described provides a devicewhich may be clampingly gripped to a webbing strap W, and in the clampedposition the spring 32 will be stressed so as to preload the grippingsurface 31 against the underlying webbing strap W. It will beappreciated that the preloading force applied to the strap will dependupon the use which is to be made of the device, and the load forceswhich are to be applied between the strap and the device. The tension ofthe spring 32 will, of course be adjusted accordingly by means of thescrews 36, 36, in the manner previously described.

The release control mechanism R as utilized for controlling release ofthe loading force applied by the leaf spring 32 is associated with thefinger plate 12b located between the ends of the back plate 10, and willnow be described in detail.

As shown in FIG. 5, the finger plate 12b is provided with a lug 53uponwhich an angle link 54 is swingably mounted. The link 54 islongitudinally formed with a groove 55 which provides spaced apart sideflanges 56 and 57 which are bridged at least in part by a connect ingwall portion 58 (FIG. 7). The link 54 is pivotally connected at one endwith the side flanges 56 and 57 straddling the lug 53, by means of pivotpin 59. The opposite end of the angle link 54 is connected through apivot pin 60 with one end of a manually operable lever 61 which isconstructed with an end projection 62, as best shown in FIG. 1, which isadapted in an extended position of the lever to abut an adjacent portionof the connecting wall 58 to limit counter-clockwise swinging movementof the lever to a position extending generally at an angle to the backplate 10, as shown in FIG. 7. However, the lever is freely swingable toan out-of-theway position as shown in phantom lines in FIG. 2. The anglelink 54 carries a spring engaging pin 63 which is anchored by means of aset screw 64 in a position in which the pin ends will respectivelyproject outwardly beyond the side flanges 56 and 57 (FIG. 5). Referringto FIG. 7,-the inner ends of the side flanges 56 and 57 are providedwith similarly arranged end edges 65 and 66 which converge to a point asindicated at 67, these edges forming abutment stops for limiting theswinging movement in opposite directions of the link 54 on its pivot.The spring 32 is provided with a longitudinally extending slot 67' ofsufficient width to permit the lever 61 and side flanges of the anglelink 54 to project i therethrough so as to permit movement of the springloading means S to a released position as shown in FIG. 1 and atensioned position as shown in FIG. 7. It will be seen that in thetensioned position of the spring 32, as shown in FIG. 7, the edge 66provides an abutment stop which will oppose clockwise movement of theangle link 54 about its pivot when the tensioned spring 32 is inengagement with the spring engaging pin 63. Likewise, in the positionshown in FIG. 1, the edge 65 forms a stop abutment which limitscounter-clockwise swinging movement of the angle link 54.

From the foregoing description it will be apparent that with a springloading force applied to the gripping means, the serrated surface 31will retain the device and webbing W against relative movement until theloading force is exceeded. However, until this point is reached, theloading pressure of the spring 32 may be controllably released with ahigh degree of nicety simply by pulling the lever 61 in acounter-clockwise direction, this action tending to bow the spring 32 ina direction to relieve the spring pressure acting on the serratedsurface 31.

Due to the relatively high spring loading pressure which will be appliedbetween the serrated surface 31 and the webbing strap W, relativemovement of the strap will subject the contact point immediately belowthe rotatable sleeve 30 to increased wear. It is therefore desirable toprovide a surface in this area which may be extremely adverse to wearconditions and this may be done by-impregnating the surface of the backplate at this location with a suitable material, as indicated by numeral68, such as tungsten-carbide, which can be done by known methods.

From the foregoing description and drawings, it will be clearly evidentthat the delineated objects and features of the invention will beaccomplished.

Various modifications may suggest themselves to those skilled in the artwithout departing from the spirit of my invention, and, hence, I do notwish to be restricted to the specific forms shown or uses mentioned.

lclaim:

l. A device of the character described for manually varying andcontrolling a gripping force applied to a connected flexible member topermit relative restrained movements between the device and the flexiblemember under a stressing loading force, comprising:

a. a body structure for receiving an elongate flexible member for axialmovements therein; means carried by said body including grippingsurfaces supported for movement into and out of engagement with saidflexible member;

c. means including a leaf spring for resiliently urging said grippingsurfaces into pressure engagement against said flexible member; and

. manually operable means carried by said body for releasably varyingsaid pressure engagement so as to enable relative restrained movementsbetween the gripping surfaces and said flexible member under appliedstressing forces, including a swingably mounted camming lever forrelieving the urging force of said resilient means with respect to saidgripping surfaces.

2. A device according to claim 1, wherein the camming lever isarticulated and includes a foldable handle portion.

3. A device according to claim 1, wherein the camming lever includes acamming link portion pivoted on saidbody structure for swingingmovement, said link portion having a part engageable with said leafspring, whereby movement of said camming link portion in one directionopposes the urging force of said spring.

4. A device according to claim 3, whereby the camming link portion hasabutment surfaces for limit-' ing the extent of movement of said camminglink portion in opposite directions of its pivotal movement.

5. A device according to claim 3, wherein the camming lever includes aextension handle portion pivoted on said camming link portion formovement from a normal operative position to a folded out-of-thewayposition.

6. A device of the character described for manually varying andcontrolling a gripping force applied to a connected webbing strap topermit relative restraint movements between the device and the webbingstrap under a stressing loadingforce, comprising:

a. a body structure including a guiding channel through which thewebbing strap is axially movable;

b. means carried by said body including a first gripping surface forengaging one side of the webbing strap and a second gripping surfacecarried on a rotatable member supported for translatory movement intoand out of engagement with an opposite side of the webbing strappositioned in said channel, the support for said rotatable membercomprising a bracket mounted for float- 4 ing and swinging movementabout a pivotal axis whereby to enable its gripping surface toautomatically accommodate to the engaged webbing strap surface; c.prestressed spring means for applying a loading and to force it againstthe first gripping surface; and

. manually operable means carried by said body for changing the springstress and consequent pressure engagement so as to enable relativerestrained movements between the gripping surfaces and said webbingstrap.

7. A device of the character described for manually varying andcontrolling a gripping force applied to a connected webbing strap topermit relative restrained movements between the device and the webbingstrap under a stressing loading force, comprising:

a. a body structure including a guiding channel through which thewebbing strap is axially movable;

b. means carried by said body including a first gripping surface forengaging one side of the webbing strap and a second gripping surfacesupported for movement into and out of engagement with an opposite sideof said webbing strap, and being carried by'a bracket mounted on saidbody structure for swinging about a pivotal axis extending transverselyof said body structure;

. prestressed spring means for applying a loading force for urging saidsecond gripping surface into pressure engagement against said webbingstrap and to force it against the first gripping surface, said springmeans comprising an elongate leaf spring connected at one end with saidbracket for swinging movement therewith and having an outer endpositionable ,in engagement with said body structure at a locationlongitudinally spaced from the pivotal axis of said bracket;

. means for releasably securing said spring outer end in a clampedengaged position with respect to said body structure; and

e. manually operable means carried by said body for changing the springstress and consequent pressure engagement so as to enable. relativerestrained movements between the gripping surfaces and said webbingstrap.

8. A device according to claim 6, wherein said guiding channel has aside opening for receiving the webbing strap sidewise into said guidingchannel and retaining means operably movable with said spring andbracket for extending across said side opening in the secured positionof the outer end of said leaf spring.

9. A device according to claim 6, wherein the means for releasablysecuring said outer end includes a manually operable lever having acamming surface engaged with said spring.

10. A device according to claim 9, wherein said camming lever has adwell surface operable at said clamped engaged position of said spring.

-l1. A device according to claim 10, including means for releasablylatching said camming lever at said clamped engaged position of saidspring.

1. A device of the character described for manually varying andcontrolling a gripping force applied to a connected flexible member topermit relative restrained movements between the device and the flexiblemember under a stressing loading force, comprising: a. a body structurefor receiving an elongate flexible member for axial movements therein;b. means carried by said body including gripping surfaces supported formovement into and out of engagement with said flexible member; c. meansincluding a leaf spring for resiliently urging said gripping surfacesinto pressure engagement against said flexible member; and d. manuallyoperable means carried by said body for releasably varying said pressureengagement so as to enable relative restrained movements between thegripping surfaces and said flexible member under applied stressingforces, including a swingably mounted camming lever for relieving theurging force of said resilient means with respect to said grippingsurfaces.
 1. A device of the character described for manually varyingand controlling a gripping force applied to a connected flexible memberto permit relative restrained movements between the device and theflexible member under a stressing loading force, comprising: a. a bodystructure for receiving an elongate flexible member for axial movementstherein; b. means carried by said body including gripping surfacessupported for movement into and out of engagement with said flexiblemember; c. means including a leaf spring for resiliently urging saidgripping surfaces into pressure engagement against said flexible member;and d. manually operable means carried by said body for releasablyvarying said pressure engagement so as to enable relative restrainedmovements between the gripping surfaces and said flexible member underapplied stressing forces, including a swingably mounted camming leverfor relieving the urging force of said resilient means with respect tosaid gripping surfaces.
 2. A device according to claim 1, wherein thecamming lever is articulated and includes a foldable handle portion. 3.A device according to claim 1, wherein the camming lever includes acamming link portion pivoted on said body structure for swingingmovement, said link portion having a part engageable with said leafspring, whereby movement of said camming link portion in one directionopposes the urging force of said spring.
 4. A device according to claim3, whereby the camming link portion has abutment surfaces for limitingthe extent of movement of said camming link portion in oppositedirections of its pivotal movement.
 5. A device according to claim 3,wherein the camming lever includes a extension handle portion pivoted onsaid camming link portion for movement from a normal operative positionto a folded out-of-the-way position.
 6. A device of the characterdescribed for manually varying and controlling a gripping force appliedto a connected webbing strap to permit relative restraint movementsbetween the device and the webbing strap under a stressing loadingforce, comprising: a. a body structure including a guiding channelthrough which the webbing strap is axially movable; b. means carried bysaid body including a first gripping surface for engaging one side ofthe webbing strap and a second gripping surface carried on a rotatablemember supported for translatory movement into and out of engagementwith an opposite side of the webbing strap positioned in said channel,the support for said rotatable member comprising a bracket mounted forfloating and swinging movement about a pivotal axis, whereby to enableits gripping surface to automatically accommodate to the engaged webbingstrap surface; c. prestressed spring means for applying a loading forcefor urging said second gripping surface into pressure engagement againstsaid webbing strap and to force it against the first gripping surface;and d. manually opErable means carried by said body for changing thespring stress and consequent pressure engagement so as to enablerelative restrained movements between the gripping surfaces and saidwebbing strap.
 7. A device of the character described for manuallyvarying and controlling a gripping force applied to a connected webbingstrap to permit relative restrained movements between the device and thewebbing strap under a stressing loading force, comprising: a. a bodystructure including a guiding channel through which the webbing strap isaxially movable; b. means carried by said body including a firstgripping surface for engaging one side of the webbing strap and a secondgripping surface supported for movement into and out of engagement withan opposite side of said webbing strap, and being carried by a bracketmounted on said body structure for swinging about a pivotal axisextending transversely of said body structure; c. prestressed springmeans for applying a loading force for urging said second grippingsurface into pressure engagement against said webbing strap and to forceit against the first gripping surface, said spring means comprising anelongate leaf spring connected at one end with said bracket for swingingmovement therewith and having an outer end positionable in engagementwith said body structure at a location longitudinally spaced from thepivotal axis of said bracket; d. means for releasably securing saidspring outer end in a clamped engaged position with respect to said bodystructure; and e. manually operable means carried by said body forchanging the spring stress and consequent pressure engagement so as toenable relative restrained movements between the gripping surfaces andsaid webbing strap.
 8. A device according to claim 6, wherein saidguiding channel has a side opening for receiving the webbing strapsidewise into said guiding channel and retaining means operably movablewith said spring and bracket for extending across said side opening inthe secured position of the outer end of said leaf spring.
 9. A deviceaccording to claim 6, wherein the means for releasably securing saidouter end includes a manually operable lever having a camming surfaceengaged with said spring.
 10. A device according to claim 9, whereinsaid camming lever has a dwell surface operable at said clamped engagedposition of said spring.